[SLC] AbstractSymbolLightClassesByPsiTest: add more stable order

Now more diff between sources and libraries are readable.
Also prefer .descriptors to .fir as FIR is a first-class support

^KT-62892

compiler/testData/asJava/lightClasses/lightClassByPsi/facades/inlineOnly.descriptors.java

@@ -0,0 +1,5 @@
+public final class InlineOnlyKt /* InlineOnlyKt*/ {
+  @kotlin.Suppress(names = {"INVISIBLE_MEMBER", "INVISIBLE_REFERENCE"})
+  @kotlin.internal.InlineOnly()
+  private static final void foo();//  foo()
+}